The study was conducted over a year-long period across the United States. The experiment involved an online classified ad selling iPods. The ads featured the same a silver, 8GB Apple iPod Nano, but with different models: one was held by a man's hand that was black, another that was white, and another that was white with a wrist tattoo. Researchers placed around 1,200 ads in more than 300 cities throughout the country.

Findings revealed that the ad featuring the black seller received 13 percent fewer responses, 18 percent fewer offers and 11-12 percent offers that were lower than their white seller counterparts. Similarly, the white seller with a wrist tattoo was almost as unsuccessful.

Research also found that black sellers did better in areas where a larger share of the local population was black, suggesting that buyers might have a preference for own-race sellers.

The unexpected results even shocked the researchers. Co-author of the study and University of Virginia professor Jennifer Doleac, said, "We were really struck to find as much racial discrimination as we did."